I’ve read my fair share of mystery novels. It’s a genre I enjoy, although I’m not an expert sleuth. Even so, after years of exposure to mystery stories and “true crime” TV shows I think I’ve got the hang of what an aspiring villain should not do when committing a murder. It’s pretty straightforward – just look at those who got caught and what they did wrong, and avoid repeating the same mistakes.
The first thing a villain must do if committing the perfect murder is have a plan. Whatever the villain does, he/she must not commit a murder at the spur of the moment. The reasons for this are evident in the subsequent rules that follow.
Rule #1: No crimes of passion.
Another painfully obvious observation from true crime stories is that law enforcement is always looking for links between the victim and the killer. These include relatives, in-laws, co-workers, bosses, love interests, and rivals. Clearly, as detectives find and identify links, they hope to discover all possible suspects and then narrow in on the guilty party.
Rule #2: No known relationship to the victim.
Hitchcock’s 1951 movie Strangers on a Train gives us an interesting twist on this rule. In the story two men who meet on a train explore the idea of each killing someone the other wishes to have killed. One wishes his wife dead and the other wants his father dead so he can get his inheritance. Because they are otherwise strangers, this “exchange” of murders represents a good example of Rule #2.
However, another thing that becomes obvious from these stories is that people who go soliciting other people to do their killing make a crucial mistake: now at least one other person knows about their nefarious plan. If the other person goes to the police (before or after any murders happen) the villain is exposed.
Rule #3: Confide in no one.
This was the error made by the murderer in Hitchcock’s movie. Once one of them killed his co-conspirator’s intended victim, the co-conspirator knew he did it. Later a witness verified who the killer was when the “innocent” co-conspirator refused to go through with his side of the deal.
So, we come to the situation where the villain must do the dirty deed himself. The first smart thing to do is to make sure that no forensic evidence is left at the scene of the crime:
Rule #4 Leave no forensic evidence at the crime scene.
Next, it is wise to put as much time and space between the villain and the victim’s death as possible. The classic example of this is the killer secretly damaging the brake lines on the victim’s car. Later, the victim drives down a dangerous road and the brakes fail, causing the car to fall down an embankment and kill the driver. Naturally, the villain is careful not to leave a trace that he was the one who damaged the brakes. Also, the villain is many miles away at the time and place of the driver’s death. A similar but more dramatic approach is to mount an exploding device under the victim’s car. The car ignition could turn on the device and blow up the car and its occupant. Even better, the use of a time delay would trigger the explosion some time later, likely after the car was driven away. This scheme increases the likelihood that the car is moving when the explosion occurs, probably making the crime scene more complicated for the police to analyze.
Rule #5: Ensure separation in time and space between the killer’s actions and the time/place of the murder. Go for the appearance of an accident.
Complying with all the above rules is very nearly impossible. Thus, the villain needs a technological solution in order to achieve the perfect murder. Specifically, the villain needs a non-human (i.e. robot) co-conspirator that can do the dirty work yet never “spill the beans.” This could be something as simple as a flying drone programmed to fly to the victim’s location and crash/explode on them (essentially a smart bomb). Or it could be a sophisticated humanoid robot that gets the job done much like a human would (using a gun, knife, explosives, fisticuff, etc.). As long as these robotic devices are not traceable back to the villain, and the villain ensures he has a solid alibi, a perfect murder appears possible.
Now having laid down the theoretical requirements for the perfect murder mystery, there is only one concern left to address. If, as Rule #2 states, the villain has no relationship with the victim, why would they want to kill them? In true crimes, interestingly, this situation occurs rather often. It occurs every time a drug addict kills a stranger while attempting to rob them.